@"R Baggett" said:
... It is a VERY old and rare house electrical service that has only 120V.
Ah, so there was historically something like I described then?
Indeed, some rural areas had service at a price fixed per light bulb. In the city, some buildings were originally lit by Edison's 100VDC system, and these were originally converted by simply hooking up to (Then standard) 110VAC when the local DC generators were decommissioned. (Due to line resistance, the voltage at the DC generator terminals was usually 110-120V or so.)
You can still find some old 110VDC fans around in the antique shops!
@evanh said:
I was thinking more like 1950s era, and using small overhead pole transformers.
Yes, there were some holdouts well into the 1980s (My detailed knowledge of house wiring stops about 1989, when I left resi wiring forever...) I did a few service changes for some rural 120V only (And even in town...) that were using old air-cooled transformers. I've never seen a pole transformer without the 120/240V secondary.. but the feeder to the house would be a bare messenger (CT and Ground) with one insulated conductor with scary brittle insulation.
Bringing back a memory.. that last resi job.. A cat hoarder's house.. I left, turned in the company truck and went to work for an industrial contractor the next week! Yes, even sewage lift stations were a more pleasant place!
Not in my experience. I'm sure there were some though. anything that could be done probably was.
In my guess, the first use for the transformers was in factories or in town replacing the DC systems. It would make sense to use a poly-phase system for this.
In the factory, the CTs make for a convenient lighting system in addition to driving 3 phase motor loads. just add a neutral.
In town for lighting, it makes sense to use CTs because you can use less copper by sharing a single neutral between 3 phases.
So you end up with a lot of CT transformers and maybe it makes sense to hang them in a rural area to feed 110V from only one side in case they get neighbors...
In Ugly's reference, there are examples of connections every permutation of the above and more. Only a few I have seen in actual practice...and I have seen a lot of systems..
Regarding Macca's failed Edge Card, there is another area that could be checked out. The VIO regulator for pins P28..P31. I was reminded that that supply runs the RCFAST oscillator, as well as the others. If RCFAST is dead then the whole IC becomes bricked.
Regulator V2431 might run hot if there is an internal Prop2 problem. This would only be a confirmation of where the problem is. There's no repairing of internal failure around those pins.
Comments
Ah, so there was historically something like I described then?
Indeed, some rural areas had service at a price fixed per light bulb. In the city, some buildings were originally lit by Edison's 100VDC system, and these were originally converted by simply hooking up to (Then standard) 110VAC when the local DC generators were decommissioned. (Due to line resistance, the voltage at the DC generator terminals was usually 110-120V or so.)
You can still find some old 110VDC fans around in the antique shops!
I was thinking more like 1950s era, and using small overhead pole transformers.
Yes, there were some holdouts well into the 1980s (My detailed knowledge of house wiring stops about 1989, when I left resi wiring forever...) I did a few service changes for some rural 120V only (And even in town...) that were using old air-cooled transformers. I've never seen a pole transformer without the 120/240V secondary.. but the feeder to the house would be a bare messenger (CT and Ground) with one insulated conductor with scary brittle insulation.
Bringing back a memory.. that last resi job.. A cat hoarder's house.. I left, turned in the company truck and went to work for an industrial contractor the next week! Yes, even sewage lift stations were a more pleasant place!
So those were all 240 V centre-tapped? There wasn't any transformer secondary's at half that?
Not in my experience. I'm sure there were some though. anything that could be done probably was.
In my guess, the first use for the transformers was in factories or in town replacing the DC systems. It would make sense to use a poly-phase system for this.
In the factory, the CTs make for a convenient lighting system in addition to driving 3 phase motor loads. just add a neutral.
In town for lighting, it makes sense to use CTs because you can use less copper by sharing a single neutral between 3 phases.
So you end up with a lot of CT transformers and maybe it makes sense to hang them in a rural area to feed 110V from only one side in case they get neighbors...
In Ugly's reference, there are examples of connections every permutation of the above and more. Only a few I have seen in actual practice...and I have seen a lot of systems..
Err, I meant no neutral, 110 V with CT (55 V each side) to the stake. I now guess it never was that way so I completely imagined it.
I've never seen such a thing...
I don't know that it never was.. It was wild until enough blood & ashes accumulated to start writing rules.
Appreciated, thanks for sticking with me.
Regarding Macca's failed Edge Card, there is another area that could be checked out. The VIO regulator for pins P28..P31. I was reminded that that supply runs the RCFAST oscillator, as well as the others. If RCFAST is dead then the whole IC becomes bricked.
Regulator V2431 might run hot if there is an internal Prop2 problem. This would only be a confirmation of where the problem is. There's no repairing of internal failure around those pins.